Package org.apache.velocity.tools.generic

Class MathTool

  • @DefaultKey("math")
public class MathTool
extends FormatConfig

    Tool for performing math in Velocity.

    Some things should be noted here:

    • This class does not have methods that take primitives. This is simply because Velocity wraps all primitives for us automagically.
    • No null pointer, number format, or divide by zero exceptions are thrown here. This is because such exceptions thrown in template halt rendering. It should be sufficient debugging feedback that Velocity will render the reference literally. (e.g. $math.div(1, 0) renders as '$math.div(1, 0)')

     Example tools.xml config:
 <tools>
   <toolbox scope="application">
     <tool class="org.apache.velocity.tools.generic.MathTool"/>
   </toolbox>
 </tools>

    Version:
    $Revision$ $Date$
    Author:
    Nathan Bubna, Leon Messerschmidt

    • Constructor Detail

      • MathTool

        public MathTool()

    • Method Detail

      • sub

        public Number sub​(Object... nums)
        Parameters:
        nums - the numbers to be subtracted
        Returns:
        the difference of the numbers (subtracted in order) or null if they're invalid
        See Also:
        toNumber(java.lang.Object)

      • mul

        public Number mul​(Object... nums)
        Parameters:
        nums - the numbers to be multiplied
        Returns:
        the product of the numbers or null if they're invalid
        See Also:
        toNumber(java.lang.Object)

      • div

        public Number div​(Object... nums)
        Parameters:
        nums - the numbers to be divided
        Returns:
        the quotient of the numbers or null if they're invalid or if any denominator equals zero
        See Also:
        toNumber(java.lang.Object)

      • pow

        public Number pow​(Object num1,
                  Object num2)
        Parameters:
        num1 - the first number
        num2 - the second number
        Returns:
        the first number raised to the power of the second or null if they're invalid
        See Also:
        toNumber(java.lang.Object)

      • idiv

        public Integer idiv​(Object num1,
                    Object num2)
        Does integer division on the int values of the specified numbers.

        So, $math.idiv('5.1',3) will return '1', and $math.idiv(6,'3.9') will return '2'.

        Parameters:
        num1 - the first number
        num2 - the second number
        Returns:
        the result of performing integer division on the operands.
        See Also:
        toInteger(java.lang.Object)

      • mod

        public Integer mod​(Object num1,
                   Object num2)
        Does integer modulus on the int values of the specified numbers.

        So, $math.mod('5.1',3) will return '2', and $math.mod(6,'3.9') will return '0'.

        Parameters:
        num1 - the first number
        num2 - the second number
        Returns:
        the result of performing integer modulus on the operands.
        See Also:
        toInteger(java.lang.Object)

      • max

        public Number max​(Object... nums)
        Parameters:
        nums - the numbers to be searched
        Returns:
        the largest of the numbers or null if they're invalid
        See Also:
        toNumber(java.lang.Object)

      • min

        public Number min​(Object... nums)
        Parameters:
        nums - the numbers to be searched
        Returns:
        the smallest of the numbers or null if they're invalid
        See Also:
        toNumber(java.lang.Object)

      • ceil

        public Integer ceil​(Object num)
        Parameters:
        num - the number
        Returns:
        the smallest integer that is not less than the given number

      • floor

        public Integer floor​(Object num)
        Parameters:
        num - the number
        Returns:
        the integer portion of the number

      • round

        public Integer round​(Object num)
        Rounds a number to the nearest whole Integer
        Parameters:
        num - the number to round
        Returns:
        the number rounded to the nearest whole Integer or null if it's invalid
        See Also:
        Math.rint(double)

      • roundTo

        public Double roundTo​(Object decimals,
                      Object num)
        Rounds a number to the specified number of decimal places. This is particulary useful for simple display formatting. If you want to round an number to the nearest integer, it is better to use round(java.lang.Object), as that will return an Integer rather than a Double.
        Parameters:
        decimals - the number of decimal places
        num - the number to round
        Returns:
        the value rounded to the specified number of decimal places or null if it's invalid
        See Also:
        toNumber(java.lang.Object)

      • getRandom

        public Double getRandom()
        Returns:
        a pseudo-random Double greater than or equal to 0.0 and less than 1.0
        See Also:
        Math.random()

      • random

        public Number random​(Object num1,
                     Object num2)
        This returns a random Number within the specified range. The returned value will be greater than or equal to the first number and less than the second number. If both arguments are whole numbers then the returned number will also be, otherwise a Double will be returned.
        Parameters:
        num1 - the first number
        num2 - the second number
        Returns:
        a pseudo-random Number greater than or equal to the first number and less than the second
        See Also:
        Math.random()

      • toInteger

        public Integer toInteger​(Object num)
        Converts an object with a numeric value into an Integer Valid formats are Number or a String representation of a number
        Parameters:
        num - the number to be converted
        Returns:
        a Integer representation of the number or null if it's invalid

      • toDouble

        public Double toDouble​(Object num)
        Converts an object with a numeric value into a Double Valid formats are Number or a String representation of a number
        Parameters:
        num - the number to be converted
        Returns:
        a Double representation of the number or null if it's invalid

      • toNumber

        public Number toNumber​(Object num)
        Converts an object with a numeric value into a Number Valid formats are Number or a String representation of a number. Note that this does not handle localized number formats. Use the NumberTool to handle such conversions.
        Parameters:
        num - the number to be converted
        Returns:
        a Number representation of the number or null if it's invalid

      • matchType

        protected Number matchType​(double out,
                           Number... in)
        Takes the original argument(s) and returns the resulting value as an instance of the best matching type (Integer, Long, or Double). If either an argument or the result is not an integer (i.e. has no decimal when rendered) the result will be returned as a Double. If not and the result is < -2147483648 or > 2147483647, then a Long will be returned. Otherwise, an Integer will be returned.

      • hasFloatingPoint

        protected boolean hasFloatingPoint​(String value)

      • getTotal

        public Number getTotal​(Collection collection,
                       String field)
        Get the sum of the values from a list
        Parameters:
        collection - A collection containing Java beans
        field - A Java Bean field for the objects in collection that will return a number.
        Returns:
        The sum of the values in collection.

      • getAverage

        public Number getAverage​(Collection collection,
                         String field)
        Get the average of the values from a list
        Parameters:
        collection - A collection containing Java beans
        field - A Java Bean field for the objects in collection that will return a number.
        Returns:
        The average of the values in collection.

      • getTotal

        public Number getTotal​(Object[] array,
                       String field)
        Get the sum of the values from a list
        Parameters:
        array - An array containing Java beans
        field - A Java Bean field for the objects in array that will return a number.
        Returns:
        The sum of the values in array.

      • getAverage

        public Number getAverage​(Object[] array,
                         String field)
        Get the sum of the values from a list
        Parameters:
        array - A collection containing Java beans
        field - A Java Bean field for the objects in array that will return a number.
        Returns:
        The sum of the values in array.

      • getTotal

        public Number getTotal​(Collection collection)
        Get the sum of the values
        Parameters:
        collection - A collection containing numeric values
        Returns:
        The sum of the values in collection.

      • getAverage

        public Number getAverage​(Collection collection)
        Get the average of the values
        Parameters:
        collection - A collection containing number values
        Returns:
        The average of the values in collection.

      • getTotal

        public Number getTotal​(Object... array)
        Get the sum of the values
        Parameters:
        array - An array containing number values
        Returns:
        The sum of the values in array.

      • getAverage

        public Number getAverage​(Object... array)
        Get the average of the values
        Parameters:
        array - An array containing number values
        Returns:
        The sum of the values in array.

      • getTotal

        public Number getTotal​(double... values)
        Get the sum of the values
        Parameters:
        values - The list of double values to add up.
        Returns:
        The sum of the arrays

      • getAverage

        public Number getAverage​(double... values)
        Get the average of the values in an array of double values
        Parameters:
        values - The list of double values
        Returns:
        The average of the array of values

      • getTotal

        public Number getTotal​(long... values)
        Get the sum of the values
        Parameters:
        values - The list of long values to add up.
        Returns:
        The sum of the arrays

      • getAverage

        public Number getAverage​(long... values)
        Get the average of the values in an array of long values
        Parameters:
        values - The list of long values
        Returns:
        The average of the array of values